A typical modular conveyor belt is disclosed in U.S. Pat. No. 3,870,141 issued to J. M. Lapeyre on Mar. 11, 1975. According to this patent, substantially identical modules formed by injection molding are pivotally connected to one another to form a conveyor belt of a desired length. Each module includes a plurality of elongated elements, and each elongated element has a first pivot end and a second pivot end. The plurality of elongated elements are joined together since the apertures defined in each of the first and second pluralities of pivot ends lie along a first and second pivot axis respectively. The first and second pivot axes are parallel one to the other. The link ends of one module are intermeshed and pivotally connected by means of a pivot rod to the link ends of another module until an .entire belt having the desired length and width is formed. Injection molded plastic belts built according to the teachings of this patent have been well received by industry and have many uses. U.S. Pat. No. 4,051,949 also issued to J. M. Lapeyre on Oct. 4, 1977 and discloses a belt similar to that of the 3,870,141 except it includes "raised ribs" which work in conjunction with a comb for the transfer of objects to and from the belt.
U.S. Pat. No. 4,171,045 issued on Oct. 16, 1979 also to J. M. Lapeyre, recognized the need for including a conveyor surface which would not allow objects riding on the conveying surface to slip and thereby allow the belt to pass underneath. A belt disclosed and constructed according to the teachings of the U.S. Pat. No. 4,171,045, is similar to that of the U.S. Pat. No. 4,051,949 discussed heretoforth except that selective ones of the elongated members include a plurality of "dogs" which extend above the normal portion of the conveying surface to contact and push articles on the conveying surface along such that the belt will not slip underneath.
In a similar manner, U.S. Pat. No. 4,213,527 issued June 22, 1980 to J. M. Lapeyre, et al further discloses a module for forming a link conveyor belt which has ridges or flight members extending transverse to the direction of travel for preventing the conveyor belt from slipping under articles riding on the conveyor belt surface. Similarly U.S. Pat. No. 4,170,281 issued on Oct. 19, 1979 and U.S. Pat. No. 4,080,842 issued on Mar. 22, 1978, both to Lapeyre, also show conveying belts having members extending transverse to the conveying surface for moving articles on the conveying surface along the belt such that the belt cannot slip underneath the article. U.S. Pat. No. 4,084,687 issued Apr. 18, 1978 to J. M. Lapeyre discloses a conveyor belt patent not particularly relevant to the present invention wherein the top surface is resilient or flexible, and very slick. Other modular link conveyor belt patent applications or patents by J. M. Lapeyre and/or owned by the same assignee as the present invention include: Ser. No. 483,210 entitled "Link Chain Belt" filed Apr. 14, 1983; Ser. No. 179,523 entitled "Modular Center Drive Conveyor Belt" filed Aug. 19, 1980; and U.S. Pat. No. 4,556,142 entitled "Lightweight Modular Conveyor Belt" issued Dec. 3, 1985. In addition, a patent application entitled "End-to-End Molded Conveyor Belt Module" filed Oct. 15, 1987 and having Ser. No. 110,109 (now abandoned) discloses subject matter having some similarity to the present invention in that the modules of this invention may be "end-to-end" molded in a manner similar to that discussed in the earlier application. A conveyor belt designed particularly for changing horizontal directions or flexing is disclosed in U.S. Pat. Nos. 4,153,152 and 4,184,588 also issued to J. M. Lapeyre on May 8, 1979 and Jan. 22, 1980 respectively. Although the belt described in these patents has been proven to operate very satisfactorily, it has the disadvantage of not being brick-layable or adjustable in width. This belt also requires two different types of modules and two different types of pivot rods. In addition, U.S. Pat. No. 4,290,762 issued on Sept. 22, 1981 to J. M. Lapeyre teaches a side flexing plastic module transmission chain. However, it is believed that this device is even less relevant to the present invention than the Lapeyre U.S. Pat. Nos. 4,153,152 and 4,184,588.
The "All-In-One"(.RTM.) conveyor belt manufactured by the KVP Company in Sacramento, Calif. and illustrated in FIG. 4 of U.S. Pat. No. 4,742,907 issued May 10, 1988 to Karl V. Palmaer is a modular plastic belt which can be brick-layed and therefore can be provided in different widths. However, this belt cannot handle small items, does not have a very tight turning radius, and can be driven in only one direction.
Another plastic modular belt sold by the Cambridge Wire Cloth Company of Cambridge, Md. under the name of Cam-Clean(.RTM.) and substantially described in U.S. Pat. No. 4,557,374 issued on Dec. 10, 1985 to Robert H. Bode has enlarged pivot apertures which allows some minimal flexing. However, the minimum turning radius of the Cam-Clean II belt is so great that it is not even sold for that purpose. The '374 patent, however does describe an embodiment for that purpose.
There are various wire mesh, and flat wire belts sold by both the Cambridge Wire Cloth Company and Ashworth Brothers Incorporated of Falls River, Mass. which can flex or change horizontal direction and are specifically sold for such purposes. Examples of these type belts are disclosed in U.S. Pat. Nos. 2,872,023 to Bechtel, Jr.; 3,261,451; 3,920,117; and 4,078,655 to Roinestad, and have a turning radius substantially the same as the turning radius of the "All-In-One"(.RTM.) described above. The Ashworth company also produces a belt system which can make a very small turning radius and which they identify as their "Small Radius Composite Belt". This metal belt system although being able to accomplish a very small turning radius can only flex in one direction and is made up of two parallel belts each having a different pitch. Furthermore, all wire mesh and flat wire metal belts are very heavy, and do not have the advantage of a modular plastic belts in that a multiplicity of modules cannot be brick-layed so as to provide a belt of any desired width.
Finally, U.S. Pat. Nos. 3,368,662 and 3,651,924 issued to J. J. Poerink on Feb. 13, 1968 and Homeier, et al on Mar. 28, 1972 respectively, show metal belts which include a multiplicity of individual links on pivot rods which are parallel to each other and which links use one slot and one circular hole as apertures. These belts of course, have the disadvantage of time consuming construction, the heavy weight of the metal material, and a restricted turning radius.
Thus, a review of the prior art patents and commercial belts as well as pending applications of the assignee of the present invention reveals that to date there has not been a simple and inexpensive modular conveying belt particularly designed with the capability of being able to flex in both horizontal directions and which is brick-layable such that the belt may be constructed to any desired width and length. Therefore it is an object of this invention to provide a module which can be constructed into a "Radius" conveyor belt (i.e. a belt with horizontal flexing capabilities), which can be brick-layed, and which is simple and inexpensive to construct and use.
It is another object of the present invention to provide a simple and inexpensive module formed by injection molding which may easily be assembled into a belt and which horizontally flex in both directions.
It is still another object of the present invention to provide a module for forming a radius or horizontal flexing conveyor belt with a very small turning radius which is modular and has the inherent capability of being easily repaired and replaced.
It is yet another object of the present invention to provide modules for forming a radius conveyor belt, which is suitable for being driven by present and existing drive methods and is therefore retrofittable on existing equipment.
It is also an object of the present invention to provide a conveyor belt which can turn or flex in either horizontal direction which may be manufactured to custom widths, and which can cooperate with the teeth of a comb to transfer objects to and from the belt.